80-82 degrees is not high at all.
I quote the article by Dr. Shimek in which he reviews average temperatures in most tropical coral areas :
The lower temperature limit for the most cold-tolerant reef organisms appears to be about 68 degrees Fahrenheit (20 degrees Celsius). This is about the water temperature of Midway Atoll, which has the northernmost coral reef. Although a few reef animals can live in colder water, most cannot. The average annual temperature of most coral reefs is around 82 to 84 degrees Fahrenheit (27 to 28 degrees Celsius)(see Table I and Figure 1), which seems to be the optimum for coral growth (Barnes et al. 1995, Clausen and Roth 1975, Weber and White 1976, Coles and Jokiel 1977 and 1978, Highsmith 1979). The commonly advised mini-reef temperatures of 74 to 77 degrees Fahrenheit (22 to 25 degrees Celsius) are stressing most of the animals unnecessarily and, in some cases, severely.
If you look up some sea surface temperatures (abbreviated SST) thru NOAA or something, you should find some maps that demonstrate, quite clearly, natural seasurface temperatures in these areas are commonly in the low eighties.
This doesn't necessarily mean, BTW, to raise your temperature to 84 degrees or something, but that 82 degrees is not a problem, nor should you spend money on unnecessary equipment (or stress) because of 82 degrees. :yes: